Research And Design Of Electric Forklift Control System

With the development of the power electric technology and microprocessors, electric forklift has high research value and broad application prospect increasingly. The design of the electric forklift core is forklift control system, so the research of forklift control system has a very realistic economic and social benefit.One set for the design of the application on electric forklift control system is designed and realized in the subject. The design of the main content includes the main circuit, drive circuit, control circuit and direct torque control strategy of application to asynchronous motor control.The design of main circuit, its core technical difficulty lies in the motor of the low voltage large current characteristics. Due to the electric forklift use the induction motor that has low voltage, large current. This requires the power MOSFET that has large current capacity and volume which cannot be too big, so take multiple tube parallel manners, such problem of uniform current in parallel becomes the problem which must be solved. The design of the problem for the uniform of the MOSFET, I do a lot of systematic and comprehensive simulation experiments. Determine the influence factors of uniform current in parallel and how to reasonably select parameters to produce very good uniform current effect.Driving circuit is designed based on IR2214drive chip. Detailed introduces the key technology of the chip, the driver in the MOSFET use a drive chip that drive two bridge legs, the three lower bridge legs can share a power supply, the above of the bridge leg uses an advanced way of bootstrap circuit. This largely reduces the power use, save costs and volume.Control circuit is built mainly based on TMS320F28335, direct torque control strategy applied to the motor that has low voltage, large current through the simulation experiments.Finally, according to the analysis of experimental results, a problem of asynchronous motor low frequency oscillation is found, I did a lot of simulation for the problem, in addition, I find out the reason of low frequency oscillation, influence factors and the solving methods.